Transitions in axial morphology along the Southeast Indian Ridge ...

• Main Authors: Ma, Ying, Cochran, James R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Columbia University 1996
• Subjects: Geophysics; FOS: Earth and related environmental sciences; Marine geophysics; Geomorphology; Mid-ocean ridges; Antarctic; Indian; Southeast Indian Ridge; Australian-Antarctic Discordance; Antarc*
• Online Access: https://dx.doi.org/10.7916/d8-7b3x-9f26; https://academiccommons.columbia.edu/doi/10.7916/d8-7b3x-9f26

Shipboard bathymetric and magnetic profiles across the Southeast Indian Ridge (SEIR) were analyzed in order to examine the nature of along-axis variations in axial morphology at this intermediate spreading rate ridge. Three types of axial morphology are observed along the SEIR: an axial high, a shallow (200-700 m deep) axial valley and a deep (> I 000 m deep) axial valley, An axial high is found to the east of the Australian-Antarctic Discordance (AAD) (east of 128°E) and between 82°E and 104°E, A shallow rift valley is found from 104°E to 114°E and from 82°E westward past the Amsterdam/St Paul hotspot (ASP) to about 30°S, 75°E. Deep rift valleys are found from l l4°E to 128°E in the vicinity of the AAD and from the Indian Ocean Triple Junction (IOTJ) at 25°S, 70°E to about 30°S, 75°E. The transition near 30°S occurs in an area of constant zero-age depth and does not appear to result from an increase in mantle temperature. It could be the result of the rapid increase in spreading rate along that portion ...